1. Field of the Invention
In the electro-photographic image forming apparatus, a toner image is formed on an image carrying body such as a photoreceptor and an intermediate transfer belt by a developing section, and the formed toner image is transferred to a sheet by a transferring section. Then, in the image forming apparatus, the toner image transferred to the sheet is fixed to the sheet by a fixing section, whereby an image is formed on the sheet.
Further, in the image forming apparatus, a developer storage container to supply developer to the developing section is mounted. In the developer storage container, developer composed of, for example, toner and carrier is stored. In the widely-used developer storage containers, in many cases, a container body is disposed sideways relative to an image forming apparatus. Furthermore, in the container body, in order to convey developer stored in the container body, a spiral protrusion portion is disposed on the inner circumferential surface of the container body. Then, by rotating the container body, the developer stored in the container body is conveyed to a discharging port disposed on a leading end portion of the container body, and discharged to the developing section.
Further, in order to discharge the conveyed developer from the discharging port efficiently, Patent Document 1 discloses a toner container provided with a conveying blade to scoop up the conveyed developer and to convey the developer to the discharging port.
2. Description of the Related Art
Patent Document 1: Japanese Unexamined Patent Publication No. 2009-271280
However, for example, like the case right after a new developer storage container has been mounted in an image forming apparatus, when a large amount of developer is stored in the container body, an amount of developer conveyed to a discharging port is larger than an amount of developer discharged from the discharging port. Therefore, an amount of developer in a space in the vicinity of the discharging port and the conveying blade becomes larger, and the density of the developer becomes higher. Then, the developer is compressed in the space and the fluidity of the developer lowers. As a result, there has been a problem that it becomes difficult to discharge the developer from the discharging port, right after a new developer storage container has been mounted.
Further, due to an increase in an amount of developer in the space in the vicinity of the discharging port and the conveying blade (an increase in compression ratio), there is a fear that the developer becomes solid and so-called soft aggregation occurs. Subsequently, if the developer in the state of the soft aggregation is used for development, there is a fear that the aggregation of the developer adheres on a sheet and image defects like a so-called firefly phenomenon occur. In particular, in the case where a filling rate of developer to be stored in a container is made to increase in order to reduce a replacement frequency of a developer storage container, a compression rate of developer in the space in the vicinity of the discharging port and the conveying blade becomes high, and the soft aggregation of developer tends to occur easily.